System adapted for diagnosis of large numbers of automotive road vehicles



March 8, 1966 c. R. SMALL 3,238,769

SYSTEM ADAPTED FOR DIAGNOSIS OF LARGE NUMBERS OF AUTOMOTIVE ROADVEHICLES Filed Nov. 30, 1962 6 Sheets-Sheet 1 ii 46 3? 44 I 23 Hi [In 97k 27 I? .3 I33 I I L I 57) 69 I b 4l B9 mm LIFT cur our H6 I62 I52 STRIPFAN a CHART SPARK BLOWER ENG'NE SCOPE ADV. E [E] CQIIITRQL F. RECORDER 1INDICATOR Q I I l 1 HO F /98 TACH.

INGNITION 27 P [s p H I43 WIRE'I CYL.

" IGNITION ENGNE COIL J- P'PE FUELSYSTEM BALANCEX/ I filva 0 I FUEL FLOWI58 l6 HR 'roaous R555 I EXHAUST RATE ANALYZER METER l5! FIGHB.

March 8, 1966 c. R. SMALL SYSTEM ADAPTED FOR DIAGNOSIS OF LARGE NUMBE OFAUTOMOTIVE ROAD VEHICLES 6 Sheets-Sheet 2 Filed Nov. 30, 1962 TOELECTRICAL CIRCUIT OF VEHICLEL C. R. SMALL March 8, 1966 SYSTEM ADAPTEDFOR DIAGNOSIS OF LARGE NUMBERS OF AUTOMOTIVE ROAD VEHICLES 6Sheets-Sheet 5 Filed NOV. 30, 1962 FIG. 6'.

I52 3 FAN 'a TAG" BLDWE R EXHAUS FAN CONTROL 2, ENGINE INTAKE BLOWERSCONTROL I22 INDICATOR TIMING CIRCUIT I/IOO ENGINE I I08 I I I I AMP SWEE P CIRCUIT GENERATING AMP.

I SYNCHRONIZATION I AND VE RTI CAL H ORIZONTAI.

OSCILLO SCOPE NO I CYLINDER COIL CIRCUIT I ENERGIZING I I I March 8,1966 c. R. SMALL 3 238,769

SYSTEM ADAPTED FOR DIAGNOSIS OF LARGE NUMBERS OF AUTOMOTIVE ROADVEHICLES Filed NOV. 30, 1962 FIG. 8.

s Sheets-Sheet 4 March 8, 1966 c. R. SMALL 3,238,769

SYSTEM ADAFTED FOR DIAGNOSIS OF LARGE NUMBERS OF AUTOMOTIVE ROADVEHICLES Filed Nov. 30, 1962 6 Sheets-Sheet 5 l S N ls N 2 K5 r; h 8

STO RAGE MEANS STORAG E IEAN S March 8, 1966 c. R. SMALL 3,238,769SYSTEM ADAPTED FOR DIAGNOSIS OF LARGE NUMBERS 0F AUTOMOTIVE ROADVEHICLES Filed Nov. 50, 1962 6 Sheets-Sheet 6 LOW V'BRAT'ON PASS PMETERDETECTOR FILTER Hami 7 l FIG. 14. I] r inst/5.

United States Patent SYSTEM ADAPTED FOR DIAGNOSIS OF LARGE NUMBERS OFAUTOMOTIVE ROAD VEHICLES Charles R. Small, Woodbury Heights, N.J.,assignor to Socony Mobil Oil Company, Inc., a corporation of New YorkFiled Nov. 30, 1962, Ser. No. 241,263 8 Claims. (Cl. 73-117) Thisinvention relates to automotive vehicle servicing, and more particularlyto a system for thoroughly testing and checking automotive vehicles inorder to diagnose any conditions needing correction.

There have been developed many sophisticated techniques and equipmentfor testing and checking automotive vehicles for various defects,malfunctionings and other conditions which require correction. Thesetechniques and equipment are all very specialized and are designed todiagnose only very specific conditions. Since there are a large numberof conditions which might require correction, it is a long drawn-outprocess to thoroughly test an automotive vehicle in order to provide adiagnosis which Will diagnose any condition in an automotive vehicleneeding correction, particularly if such condition is not evident to theoperator or owner of the vehicle. As a result, it is not economicallypractical for a vehicle owner to pay to have this kind of diagnosisperformed or for a garage to perform it. The usual procedure is to waituntil trouble becomes disturbing and then perform tests to determine thecause of the particular trouble and correct it. This procedure oftenresults in increased expense because the condition was not correctedsoon enough. Moreover, since the vehicle owners are not willing to paythe cost of thorough testing and checking, it is not economicallypractical for a garage to keep on hand the expensive equipment requiredto perform the more sophisticated testing techniques. As a result, manymodern testing techniques, which would more accurately diagnoseconditions requiring correction in the vehicle, are not available to thevehicle owner. The present invention provides a testing facility whichgreatly reduces the time require-d to carry out the testing procedure.The facility of the present invention comprises a drive-through diagnostic bay having test equipment located therein, including adynamometer having its rollers positioned in the driveway of thediagnostic bay adapted to engage vehicle wheels. Wheel alignmentmeasuring apparatus which has rollers positioned in the driveway of thebay adapted to engage vehicle wheels is also included in the facility.In the testing procedure the vehicle is driven to position the frontwheels thereof on the rollers of the dynamometer and then tests areperformed on the vehicle by driving the front wheels of the vehicle withthe dynamometer rollers. After these tests are performed, the vehicle isdriven forward to position the rear wheels of the vehicle on the rollersof the dynamorneter. At this time, additional test equipment isconnected to the power plant of the vehicle, including the fuel lines,the electrical system, the manifold and the exhaust pipe, and tests areperformed on the vehicle using this test equipment in combination withthe dynamometer. After the tests have been completed, the vehicle isdriven forward to position the front wheels on the wheel alignmentmeasuring apparatus and the alignment of the front wheels is measured.

The dynamometer is controlled during the test procedure by thediagnostician sitting in the drivers seat of the vehicle by means ofswitches which are on control pendants, which hang next to the driverswindow during that part of the test procedure when the dynamometer isbeing used. A control pendant is provided which hangs next to thedrivers window when the front wheels of the vehicle are on the rollersof the dynamometer and a secice 0nd control pendant is provided whichhangs next to the drivers window when the rear wheels of the vehicle areon the rollers of the dynamorneter. Thus the diagnostician sitting inthe drivers seat can control the operation of the dynamometer when thefront wheels of the vehicle are on the rollers of the dynamometer aswell as when the rear wheels of the vehicle are on the rollers of thedynamometer. A third pendant is provided which hangs next to the windowof a vehicle having its front wheels on the rollers of the wheelalignment measuring apparatus and switches on this pendant control theoperation of the wheel alignment measuring apparatus. Because thesecontrol pendants are provided which permit the test equipment to beoperated by the diagnostician sitting in the drivers seat of thevehicle, a substantial amount of time is saved, as the time which wouldotherwise be required for the diagnostician to get in and out of thevehicle is eliminated.

A large part of the test equipment which is connected to the power plantof the vehicle when the rear wheels of the vehicle are positioned on therollers of the dynamometer is mounted on an instrument carriage which issuspended from an overhead trolley. The trolley permits the instrumentcarriage to be moved throughout a small area, including a positionadjacent the front end of a vehicle having its rear wheels engaged bythe rollers of the dynamometer. This arrangement facilitates the processof connecting this equipment to the vehicle and thus saves valuabletime. It also permits the instrument carriage to be moved back out ofthe way during that part of the test procedure when it is not in use andthis also saves time. Because of the time saved by the presentinvention, it is now possible to provide an economically practicalsystem for diagnosing almost any condition which might requirecorrection in an automotive vehicle.

Accordingly, it is a principal object of the present invention toprovide an improved system for thoroughly testing and checkingautomotive vehicles.

Another object of this invention is to reduce the time and laborrequired for thoroughly testing and checking automotive vehicles.

A further object of this invention is to make thorough testing andchecking of automotive vehicles economically practical.

A still further object of this invention is to provide for improveddiagnosis of conditions requiring correction in automotive vehicles.

A still further object of this invention is to provide for improveddiagnosis of conditions in automotive vehicles needing correction inorder to reduce repair costs.

A still further object of this invention is to provide a more accuratediagnosis of conditions needing correction in automotive vehicles.

Further objects and advantages of the present invention will becomereadily apparent as the following detailed description of the inventionunfolds, and when taken in conjunction with the accompanying drawings,wherein:

FIG. 1 is a schematic illustration of the layout or floor plan of thediagnostic .bay of the invention;

FIG. 2 is a view in perspective of the diagnostic bay with portions ofthe roof and walls broken away to reveal the interior of the bay;

FIG. 3 is a block diagram illustrating how equipment in the test bay isconnected to the engine of a vehicle under diagnosis;

FIG. 4 is a block diagram illustrating the engine scope and the sparkadvance indicator and how they are interconnected in accordance with thepresent invention;

FIG. 5 illustrates structural details of the spark ad vance indicator;

'FIG. 6 is a block diagram illustrating the ventilation control systemfor the diagnostic bay;

FIG. 7 is a circuit diagram of the volt amp tester illustrating how itis connected to the vehicle engine;

FIG. 8 is a view in elevation of the Merrill wheel aligner, which isused in the system of the present invention;

'FIG. 9 is a plan view of the Merrill wheel aligner;

FIG. 10 illustrates a circuit used in the Merritt wheel aligner formeasuring caster;

FIG. 11 illustrates the horizontal stabilizer of the present inventionused in combination with the Merrill wheel aligner;

FIG. 12 illustrates a system used for measuring wheel unbalance; and

'FIGS. 13 through 15 are schematic diagrams illustrating variouspositions of a vehicle as it is processed through the diagnosticprocedure.

As illustrated in FIG. 1, the drive-through diagnostic bay has anentrance 17 and an exit 19. Automobiles to be diagnosed are driven intothe bay through the entrance 17, are tested and diagnosed, and aredriven out the exit 19. An exhaust duct 21 is provided under the floorof the drive-through bay. The duct 21 communicates with the bay througha large opening in the floor of the bay about ten feet inside of theentrance 17. This opening is covered by a grate 23, which is strongenough to support the automobiles which will be driven over it. The duct21 is connected to two vertically disposed ducts on the side wall of thedrive-through bay. The ducts 25 lead to exhaust fans, which draw airfrom the bay through the grate 23 and through the ducts 2'1 and 25 andexhaust the air outside. The air exhausted in this manner will carry outthe exhaust gases of the automobiles and keep the air in the test bayfresh. A Maxwell dynamometer 27 is also mounted in the floor of the testbay. The Maxwell dynamometer 27 has two pairs of rollers 29 and 31 forreceiving the right and left wheels of an automotive vehicle. Thesepairs of rollers are positioned in the floor of the test bay,approximately twentyone feet from entrance 17. The bay also has aMerrill wheel aligner 33 which has pairs of rollers 35 and 37 located inthe floor of the test bay. .The rollers 35 and 37 are positionedtwenty-five feet forward of the rollers 29 and 31 of the dynamometer 27towards the exit 19 and are spaced to receive the right and left wheelsof the automotive vehicles to be tested. The spacing between the rollersof the Maxwell dynamometer 27 and the rollers of the Merrill wheelaligner 33 is longer than the wheel bases of the automotive vehicles tobe tested so that a vehicle, after being tested with its rear wheels onthe rollers 29 and 31, moves forward to the position in which its frontwheels are on the rollers 35 and 37 of the Merrill wheel aligner.Because of this arrangement, valuable time in the testing procedure issaved. Suspended from overhead in the bay is an instrument carriage 39which can be moved by its suspension system anywhere within the dottedline 41. An instrument and control panel 67 mounted on the left handwall of the test bay is located approximately inthe middle of the testbay between the Maxwell dynamometer 27 and the Merrill wheel aligner 33.Two blowers 69 are located on opposite sides of the exit 19 within thetest bay. These blowers provide a supply of fresh air to the bay and areused to maintain the temperature within the diagnostic bay at thedesired level.

' The entrance 17 and the exit 19 are provided with doors which areopened and closed by positioning mechanisms. The positioning mechanismfor the door in the entrance 17 will raise this door to its openposition in response to a vehicle running over a treadle 43 positionedacross the vehicle driveway outside the entrance 17. The positioningmechanism for the entrance door will close the entrance door in responseto a vehicle running over a treadle 44 positioned inside of th entr nce17 cros the floor of the diagnostic bay between the entrance 17 and therollers 29 and 31 of the dynamometer 27. The treadle 44 is positionedsufliciently far enough from the entrance 17 for any vehicle which hasits front wheels on the treadle 44 to be out of the entrance 17. Theentrance 17 is provided with a photocell adapted to sense any vehicle orother obstruction in the entrance 17 and apply a signal indicating thepresence of such an obstruction in the entrance 17 to the positioningmechanism for the entrance door. In response to such a signal from thisphotocell the positioning mechanism for the entrance door will hold theentrance door in its raised position even if a vehicle is on the treadle44. The positioning mechanism for the door in the exit 19 will raisethis door to its open position in response to the actuation of a switchand will lower the exit door to its closed position in response to avehicle running over a treadle 46 positioned across the vehicle drivewayoutside the exit 19. The exit 19 is provided with a photocell to senseany vehicle or other obstruction in the exit 19 and apply a signalindicating the presence of such an obstruction to the positioningmechanism for the exit door. In response to receiving such a signal fromthis photocell the positioning mechanism for the exit door will hold theexit door in its open position regardless of whether a vehicle is on thetreadle 46 or not.

As will be pointed out below, some of the test equipment is mounted onthe instrument carriage 39 and some is mounted in the instrument andcontrol panel 67. The position of the instrument control panel 67 wasselected to minimize the time of making the tests with the equipmentmounted therein.

The use of the mobile instrument carriage 39 saves valuable time in thetesting procedure because it facilitates the connection of the equipmentto the vehicles being tested. FIG. 2, which shows the interior of thetest bay in perspective, illustrates how the instrument carriage 39 issuspended to be easily movable anywhere within the dotted line 41. Theinstrument carriage 39 is fixed to the lower end of a vertical post 70,the upper end of which is fixed to trolley 72. The trolley 72 isprovided with wheels 74 which roll on overhead tracks 76, the trolley 72being suspended by its wheels 74 from the tracks 76. The tracks 76extend perpendicular to the direction of vehicle trafiic in thediagnostic bay. The tracks '76 comprise two beams which are rigidly heldtogether by cross bars 78 and the assembly of the tracks 76 and crossbars 78 is suspended by wheels 80 from tracks 82, which also comprisetwo beams. The tracks 82 extend perpendicular to the tracks 76, or inother words parallel to the direction of vehicle trafiic in thediagnostic bay. The tracks 76 are movable along the length of the tracks82 on the wheels 86. Thus the instrument carriage 39 can be movedperpendicularly to the direction of vehicle traflic in the diagnosticbay by movement of the trolley 72 along the tracks 76, or can be movedparallel to the direction of vehicle traffic by movement of the tracks76 along the tracks 82, and thus can be moved anywhere within the dottedline 41.

As shown in FIGS. 1 and 2, pendants 84, 86 and 88 hanging from theceiling are spaced along the length of the diagnostic bay. Thesependants are normally re-- tracted and are extended when needed. Thependant 84 contains control switches to operate the dynamometer 27' andis positioned when extended to be operated by a person sitting in thedrivers seat of a vehicle in the position shown in FIG. 13, with itsfront wheels in the rollers 29 and 31 of the dynamometer 27. The pendant86 has switches to control the dynamometer 27 and the other equipmentused in conjunction with the dynamometer 27. The pendant 86 ispositioned when extended to be operated by a person in the drivers seatof a vehicle in the position shown in FIG. 14, with its back wheels onthe rollers 29 and 31 of the dynamometer 27. The pendant 83 has switchescontrolling the operation of the Merrill aligner 33 and is positioned tobe operated by a person sitting in the driver*s seat of a vehicle in theposition shown in FIG, 15 with its front wheels in the rollers 35 and 37of the Merrill aligner 53. The pendants 84, 86 and 88 hang frompositioning units 90, 92 and 94, respectively, and are positionable bythese units in either an extended position where they hang low enough tobe operated by the vehicle driver or in a raised position in which theyare retracted out of the way. The positioning unit 90 will lower thependant 84 in response to actuation of a switch operated by a foottreadle 96, which is positioned in the floor of the bay between the leftwall and the dynarnometer 27. The foot treadle 96 also closes a switchwhich actuates the dynamometer 27 to lower its wheel lift. Thepositioning unit 90 will raise the pendant 84 in response to actuationof a switch in the pendant 84. The positioning unit 92 will lower thependant 86 in response to actuation of a switch operated by a vehicletreadle 97 positioned across the diagnostic bay between the dynamometer27 and the Merrill wheel aligner and will raise the pendant 86 inresponse to actuation of a switch in the pendant 86. The positioningunit 94 will lower the pendant 88 in response to actuation of a switchin the pendant 86. With this arrangement, the position units 90, 92 and94 can be operated to lower the pendants 84, 86 and 88 only when theyare needed and to keep them retracted out of the way at all other times.

FIG. 3 is a block diagram illustrating the test equipment in thediagnostic bay when it is connected up with the engine of an automotivevehicle. The engine of the vehicle is designated by the reference number98. As shown in FIG. 3, an engine scope 100 has one lead con nected tothe high voltage output of the ignition coil and another lead connectedto the ignition wire of the No. 1 cylinder of the engine. The details ofthe engine scope are disclosed in the Patent No. 2,608,093, invented byAlfred E. Traver and issued on August 26, 1952, and in the copendingapplication Serial No. 172,016, entitled Analyzer for InternalCombustion Engine, filed on February 8, 1962, and invented by Alfred E.Traver. As disclosed in the Traver patent the engine scopesimultaneously depicts a plurality of vertically separated horizontalwave-forms, one for each cylinder of the engine and synchronized withthe functioning of such cylinder. FIG. 4 is a block diagram whichillustrates how the engine scope is used in the present invention. As inthe Traver patent, the scope leads are clipped over the insulation ofthe wires of the engine to be capacitively connected thereto rather thanbeing directly connected. In FIG. 4 these leads are designated by thereference numbers 102 and 104. The leads designated 102 and 104 feed thesignal voltages generated at the high voltage output of the ignitioncoil and at the ignition wire of the No. 1 cylinder to a synchronizationand sweep generating circuit 106 in the engine scope 100. The circuit106, in response to the applied signals, feeds appropriate waveforms tothe vertical and horizontal amplifiers of an oscilloscope 108, as isdisclosed in the Traver patent, in order to produce the verticallyseparated horizontal traces, each synchronized with a differentcylinder. In order to depict the waveform of the high voltage output ofthe ignition coil for each cylinder, the lead 102, which applies thesignal from the ignition coil to the synchronization and sweepgenerating circuit 106, is also connected to the input of the verticalamplifier of the oscilloscope 108. With this arrangeemnt, theoscilloscope shows the voltage waveform at the output of the ignitioncoil for each cylinder as it fires and immediately thereafter. Fromthese waveforms a diagnostician can determine the dwell for eachcylinder; he can determine whether the spark plug and the ignition wireare in satisfactory condition for each cylinder; he can determinewhether the coil, the points and the condenser are in satisfactorycondition; and he can determine whether the distributor lobes, thedistributor drive and the distributor bearings are in satisfactorycondition.

The interconnection of the synchronization circuitry 106 and theoscilloscope 108 is made internally in the engine scope, and thediagnostician only has to make two connections in order to connect theengine scope to the engine of the vehicle being tested.

As shown in FIG. 3, the movable pole of a switch 110 is connected to theprimary winding of the ignition coils of the engine 98. In one positionthe switch 110 connects the primary winding to ground, shorting it out,and in the other position the switch 110 connects the ignition coilprimary to the input of an engine tachometer 112. When the switch 110connects the primary winding of the ignition coil to the tachometer 112,the tachometer 112, in response to the pulses generated in the ignitioncoil by the action fo the breaker points, produces a visual indicationof the revolutions per minute of the engine and also produces anelectrical output signal representing this value. The electrical signalproduced by the engine tachometer 112 is fed to a strip chart recorder114. A spark advance indicator 116 is connected to the engine scope 100to produce a visual display of the basic timing of the engine andindicate the total spark advance.

FIG. 4 includes a block diagram of the spark advance indicator circuitand illustrates how it is interconnected with the engine scope. As shownin FIG. 4, the signal from the No. 1 cylinder ignition wire on lead 104is applied to a timing circuit 118 of the spark advance indicator 116.In response to each pulse on lead 104, the timing circuit 118 triggersan energizing circuit 120, which in response thereto energizes a flashtube 122. A pulse will occur on lead 104 simultaneously with each firingof the No. 1 cylinder. Thus, each time the spark plug of the No. 1cylinder fires, the flash tube 122 will be energized. The timing circuit118 will either trigger the energizing circuit immediately in responseto each pulse on lead 104 or will trigger it after a time delay which iscon tinuously and selectively variable by means of a control 124. Thetiming circuit 118 also applies a signal to an indicator 126, whichprovides a visual indication of the amount of delay provided by thetiming circuit 118. Because the spark advance indicator 116 receives itssignal from the lead 104, it does not have to be separately connected tothe engine 98, and the diagnostician, upon connecting the leads 102 and104 to the engine 98, has connected both the engine scope 100 and thespark advance indicator 116 to the engine, thus saving valuable time.

FIG. 5 illustrates the structure of the spark advance indicator. Asshown in FIG. 5, the spark advance indicator comprises a housing 128 anda remote flash unit 130 connected to the housing 128 by a cable 132. Thetiming circuit 118, the energizing circuit 120, and the indicator 126are mounted in the housing 128. The remote flash unit 130 includes theflash tube122 and the control 124. The interconnections between theflash tube 122 and the energizing circuit 120 and between the control124 and the timing circuit 118 are through the cable 132. The flash tube122 and the control 124 are mounted in a barrel casing 134 whichfunctions as a handle. The control 124 is manually operated by means ofa knob 136. By adjusting the angular position of the knob 136, the delayprovided by the timing circuit 118 can be selected.

In operation the diagnostician illuminates the timing marks in theengine 98 with the flash tube 122. This illumination will cause thetiming marks to apparently stop in stroboscopic illusion at the positionthey are in each time the flash tube 122 is energized. The timing markscooperate with a reference mark to indicate the position of the pistonin the No. 1 cylinder relative to top dead center when the flash tube122 is energized. In order to read basic timing, which is the positionof the piston in the No. 1 cylinder relative to top dead center when itfires with no distributor induced spark advance, or in other words atidle speed, the diagnostician by means of the knob 136 selects no delayby the timing circuit 118 and the engine is operated at idle speed. Thediagnostician then illuminates the timing marks with the flash tube andobserves the indication, which will be the basic timing of the engine.In order to observe the spark advance at a particular speed, the engineis operated at the speed of interest and the knob 136 is adjusted untilthe indication by the timing marks is the same as that of basic timing.The delay indicated by the indicator 126 as being provided by the timingcircuit 118 will be the spark advance at this particular speed. Becausethe control 124 is provided with the remote flash unit 130 instead of onthe housing 128, the diagnostician taking the spark advance reading isable to obtain this reading in a much shorter time.

The Maxwell dynamometer 27 has a tachometer 138 producing a signalproportional to the speed at which the rollers 29 are driven, atachometer 140 producing a signal proportional to the speed at which therollers 31 are driven, and a transducer 142 which produces an outputsignal proportional to the torque being absorbed or transmitted by themotor of the dynamometer 27. The dynamometer 27 has a third tachometer143 which like the tachometer 138 produces an output signal proportionalto the speed at which the rollers 29 are driven. The output signalproduced by the tachometer 143, which will be proportional to the wheelspeed of the vehicle, is applied to the strip chart re corder 114. Thestrip chart recorder 114 thus receives a signal proportional to thewheel speed of the vehicle and a signal proportional to the engine speedof the vehicle. The strip chart recorder 114, when it is actuated,produces a chart with two traces, one of which represents the enginer.p.m. vs. time and the other of which represents wheel speed vs. timeover the same period. From the recording done by the strip chartrecorder 114, the engine r.p.m. can be compared with the rear wheelspeed and the operation of the vehicle transmission can be analyzed. Theoutput signal from the tachometer 143 is also fed to a dynamometer liftout out circuit 145, which in response to receiving a signal from thetachometer 143 prevents the dynamometer 27 from raising its wheel lift.This circuit prevents accidental raising of the dynamometer wheel liftwhen the wheels of a vehicle are turning on the rollers of thedynamometer 27. The output signal of the tachometers 138 and 140 areapplied to averaging circuit 144, which produces an output signalproportional to the average of the output signals of the tachometers 13Sand 140 and representing the average wheel speed of the vehicle. Noaveraging is needed in the strip chart recording operation because inthis operation both rear wheels will be driven at approximately the samespeed. The output signal from the transducer 142 representing the torqueabsorbed by the dynamometer motor and the output signal of the averagingcircuit 144, which represents the wheel speed of the vehicle, are fed toa horsepower meter 146. In response to these signals the horsepowermeter 146 produces a visual indication of the horsepower transmittedbetween the vehicle wheels and the dynamometer 27. The output signalfrom the tachometer 138 and the output signal of the tachometer 140representing the right and left wheel speeds are fed to a balance meter148, which provides a visual indication of the difference in the speedsrepresented by the output signals of the tachometers 138 and 140. Thusthe balance meter 148 produces a signal representing the difference inspeeds of the right and left vehicle wheels. This balance met-er 148connected in .this manner can be used to provide an indication of thebraking balance between the wheels, the balance of horsepowertransmitted to the rear wheels, and a balance of the parasitichorsepower absor-bed by the wheels. The output signal of the averagingcircuit 144 is also fed .to an mph. meter 150, which produces a visualindication of the speed represented by the output signal of theaveraging circuit 144 and thus a visual indication of the vehicle wheelspeed. The output signal of the averaging circuit 144 is also fed to arate meter 151, which by means of a resistor and capacitor networkmeasures and indicates the rate of change of the output signal of theaveraging circuit 144. The indication of the rate meter 151 willtherefore be a measure of .the acceleration of the wheels of thevehicle.

The output signal from the engine tachometer 112 is also fed to a fanand blower control 152, which controls the rate that air is exhaustedfrom and fresh air is brought into the bay. The block diagram in FIG. 6illustrates how the .fan and blower control 152 operates. The system isprovided With two exhaust fans which exhaust air from the test baythrough the ducts 21 and 25. One of the exhaust fans runs all of thetime and the other, designated by the reference number 154 in FIG. 6, iscontrolled automatically in response to the output signal from theengine tachometer 112. When the engine tachometer 112 is not producingan output signal, the fan and blower control 152, in response to thiszero output signal of the engine tachometer 112, runs the intake blowers69 at half speed and maintains the exhaust fan 154 shut off. When theengine tachometer 112 produces an output signal, the fan and blowercontrol 152, in response to this signal, will operate the intake blowers69 at full speed and will maintain the exhaust fan 154 turned on. Inthis manner the exhaust fan 154 is run only when .the engine of thevehicle under diagnosis is being run under test with the enginetachometer 112. During the other parts of the testing when the engine ofthe vehicle is not running under test and less air exhaustion is needed,the fan 154 is automatically shut off. The intake blowers 69 areautomatically run at full speed only when the exhaust fan 154 is beingoperated, thus providing an increased supply of temperature-conditionedair when the exhaust fan 154 is running. Thus the amount of air beingexhausted from the diagnostic bay and the amount of fresh air beingbrought into the diagnostic bay are automatically increased when theengine of a vehicle is being run under test in the diagnostic bay.

As shown in FIG. 3, a tube 156 is connected to sample exhaust from theexhaust pipe of the engine 98. The tube 156 feeds a sample of theexhaust gas to an exhaust analyzer 158, which measures the percentage ofCO in the exhaust gas and produces a visual indication of thismeasurement. This indication reflects the combustion efiiciency of theengine 98. A vacuum gauge 160 is connected to measure the vacuum at theintake manifold and produces a visual indication of this measurement. Avolt amp tester 162 is connected to measure the generator current and tomeasure the voltage between the regulator battery terminal and ground.The volt amp tester 162 is used to provide an indication of theregulated generator output amperage and voltage and also an indicationof the amperage when the cutout relay of the regulator opens and thevoltage at which it closes. It is also used to provide an indication ofthe cranking battery voltage. The volt amp tester of the presentinvention requires only three leads instead of the usual five. Becauseof this fact, the diagnostician has to connect only three leads betweenthe volt amp tester and the engine, and as a result valuable time issaved. FIG. 7 is a circuit diagram illustrating the circuit of the voltamp tester and how it is connected to the electrical system of thevehicle under diagnosis. In FIG. 7 the vehicle battery is designated bythe reference number 164, the vehicle generator by the reference number166, and the regulator by the reference number 168. In a conventionalvehicle electrical system one side of the battery is grounded and theother side of the battery is connected to one terminal of the generatorthrough the regulator, the other terminal of the generator beinggrounded. The junction between the battery and the regulator isconnected to the vehicle electrical circuit including the ignitionswitch, the starter motor, the ignition coil, the lights, horn, etc. InFIG. 7 the lead which in the electrical system connects the vehiclecircuit to the junction between the battery 164 and the regulator 168 isdesignated by the reference number 170. The volt amp tester 162comprises a voltmeter 172 and an ammeter 174. One terminal of thevoltmeter 172 is connected to one terminal of the ammeter internally inthe volt amp tester. The three leads of the volt amp tester aredesignated by the reference numbers 176, 178 and 180. The lead 178 isconnected to the junction between the voltmeter 172 and the ammeter 174.The lead 176 is connected to the other terminal of the voltmeter 172 andthe lead '180 is connected to the other terminal of the ammeter 174. Aswitch 181 and a load resistor 183 are connected in series across thevoltmeter 172 between the lead 176 and the lead 178.

As shown in FIG. 7, when the volt amp tester is connected to theelectrical system of the vehicle, the lead running between the lead 170and the regulator 168 is disconnected from the terminal of theregulator, which is designated 182, and connected to the lead 180. Thelead 178 is connected to the terminal 182 and the lead 176 is connectedto the ground. In this manner when the switch 181 is open the electricalsystem of the vehicle is connected to function normally with the ammeter174 connected to measure the current flowing between the regulator 168and the lead 170, or in other words the current of the generator 166 andthe voltmeter 172 connected to measure the voltage between the terminal182 and ground. When the switch 181 is closed it imposes a known loadprovided by the resistor 183 on the generator so that the regulatedoutput of the generator so that the regulated output of the generatorcan be checked under a known load.

As shown in FIG. 3, a flow meter 184 is connected by means of fuel lines186 and 188 between the fuel pump and the carburetor to measure the rateof fuel flow. A fuel pressure gauge 190 is connected to the fuel linebetween the fuel pump and the carburetor to measure the fuel pumppressure. When the fuel flow meter 184 is connected up with the fuelsystem, it, together with the fuel lines 186 and 188, is connected inseries with the regular fuel line between the fuel pump and thecarburetor. To eliminate the labor of separately connecting the fuelpressure gauge 190 to the engine fuel line, the fuel pressure gauge 190is connected permanently to the fuel line 186. Thus once the flow meter184 is connected in the fuel system of the vehicle, the pressure gauge190 will also be connected to measure the fuel pressure between the fuelpump and the carburetor.

The engine scope 100, the spark advance indicator 116, the volt amptester 162, the manifold vacuum gauge 160, the fuel flow meter 184 andthe fuel pressure gauge 190 are all mounted in the instrument carriage39, which is suspended from overhead to be feely movable within thedashed line 41 as descibed above, so that these instruments may beeasily connected to the vehicle to be tested. The instruments mounted onthe instrument carriage 39 all retract their leads into the carriage 39when the leads are not in use. The fan control 152 and the strip chartrecorder 114, the balance meter 148, the horsepower meter 146, them.p.h. meter 150, the rate meter 151, the engine tachometer 112, and theexhaust gas analyzer 158 are mounted in the instrument and control panel67.

The above described instruments will be connected to the engine of thevehicle in the manner described when the vehicle is being tested on theMaxwell dynamometer 27. After being tested on the Maxwell dynamometer 27the vehicle is then advanced until its front wheels fall into therollers 35 and 37 of the Merrill aligner 33. The Merrill aligner 33provides a visual indication of the caster and camber of the left wheel,a visual indication of the caster and camber of the right 10 wheel, anda visual indication of the total toe of the front wheels. In the Merrillaligner the rollers 35 and 37 are mounted on carriages. When the frontwheels of the vehicle under diagnosis are on the rollers 35 and 37, therollers 35 and 37 are driven at a constant speed by electric motors andin turn the rollers 35 and 37 drive the front wheels of the vehicle.Means are provided in the carriages mounting the rollers 35 and 37 toposition the rollers 35 and 37 so that the axes of the rollers 35 areparallel with the axis of the right front wheel of the vehicle and theaxes of the rollers 37 are parallel with the left front wheel of thevehicle. FIGS. 8 and 9 show the details of the carriage mounting therollers 37 and illustrate how the carriage aligns the axes of therollers 37 parallel with the axis of the left front wheel. The carriagemounting the rollers 35 aligns the axes of the rollers 35 with, the axisof the right front wheel in the same manner that the carriage mountingthe rollers 37 aligns the rollers 37. As shown in FIGS. 8 and 9, therollers 37 are driven by electric motor 192 which is also mounted on thecarriage. The carriage comprises a base 194, on which the electric motor192 is mounted, and an upper bracket 196 which is pivotable with respectto the base 194 and on which the rollers 37 are rotatably mounted. Thebracket 196 pivots on the base 194 about a pivot point designated 198and the amount that the bracket 196 is pivoted with respect to the base194 is controlled by means of a hydraulic servo unit 200. The base 194is mounted on rollers 202 and is pivotable about a fixed vertical axis204 on the rollers 202. When the rollers 37 are driving the front wheelof the vehicle the base 194 will pivot about the vertical axis 204 dueto forces exerted on the rollers 37 until the horizontal components ofthe axes of the rollers 37 are parallel with the horizontal component ofthe axis of the vehicle Wheel. However, due to the camber of the wheel,the axes of the rollers 37 will still not necessarily be parallel withthe axis of the wheel. The hydraulic servo unit 200 will pivot thebracket 196 with respect to the base 194 until the axes of the rollers37 are parallel with the axis of the vehicle wheel. To provide thecontrol for the hydraulic servo unit 200 to achieve this result, therollers 37 are axially slidable short distances on their axles 206. Whenthe rollers 37 are driving the vehicle wheel and the axis of the vehicleWheel due to its camber is not aligned with the axes of the rollers 37,the vehicle wheel will exert forces on the rollers 37 sliding them toone side or the other, depending upon the direction of the misalignment.The rollers 37, on being slid to one side, will actuate a microswitch,and in response to the actuation of this microswitch the hydraulic servounit 200 will be energized to change the angular position of the bracket196 with respect to the base 194 in a direction to eliminate themisalignment of the axis of the vehicle wheel with the axes of therollers 37. Similarly, when the rollers 37 are slid to the other side inresponse to the misalignment being in the opposite direction, therollers 37 will actuate a microswitch, in response to which thehydraulic servo unit 200 will change the angular position of the bracket196 with respect to the base 194 in the opposite direction until themisalignment is eliminated. In this manner the axes of the rollers 37are made parallel with the axis of the vehicle wheel. A potentiometer208 produces an output signal representing the angular position of thebase 194 with respect to the fixed vertical axis 204. When the rollers37 have been aligned with the vehicle wheel, the output signal of thepotentiometer 208 will therefore represent the toe of the vehicle wheel.A potentiometer 2'10 produces an output signal representing the angularposition of the bracket 196 with respect to the base 194. When therollers 37 have been aligned with the vehicle wheel, the output signalof the potentiometer 210 will represent the camber of the vehicle wheel.The carriage supporting the rollers 35 produces output signalsrepresenting toe and camber in the same manner. To obtain the caster ofa vehicle wheel on the rollers 37, the Merrill aligner uses the circuitillustrated in FIG. 10. While the rollers 37 drive the vehicle wheelthereon and the rollers are maintained aligned therewith, the vehiclewheels are turned 7 /z to the right. The output signal voltage of thepotentiometer 210 when the wheels are turned 7 /2 to the right is storedin a storage means 207. The vehicle wheels are then turned 7 /2 to theleft and the output signal voltage of the potentiometer 210 is stored ina storage means 209. A differential amplifier 211 then amplifies the difference between the signal voltage stored in the storage means 207 andthat stored in the storage means 209 and applies a signal proportionalto this difference to a meter 213, which provides an indication of thissignal. When these operations have been carried out, the output signalof the differential amplifier 211 will be proportional to and the meter2 13 will indicate the caster of the wheel in the rollers 37. Anidentical circuit is provided for the rollers 35 to measure the casterof the wheel in these rollers in the same manner. The caster measuringoperations are performed simultaneously so that the wheels only need tobe turned to the right and to the left once to obtain the castermeasurement for both wheels.

When the vehicle is being tested on the Merrill aligner in this manner,it is necessary to hold the front of the vehicle in place so that itdoes not slide off the rollers to the right or the left. The device forproviding this holding is called a horizontal stabilizer. The horizontalstabilizer of the present invention, which is illustrated in FIG. 11,permits it to be quickly and easily applied to the vehicle withouthaving to actually be bolted thereto, thus saving valuable time in thediagnostic procedure. As shown in FIG. 11, the horizontal stabilizercomprises a pair of braces 212 which move transversely across thedrivethrough bay driven by hydraulic cylinders 215, on a track 214recessed beneath the floor of the drive-through bay. Carriages 217 aremounted on the braces 212 to have a limited horizontal movement withrespect to the braces 212 transverse to the direction that the bracesthemselves are moveable. The carriages 217 have rollers which engage thebraces to provide the limited motion for the carriages. Springs hold thecarriages 217 normally in the center of their range of movement. Thecarriages 217 have mounted thereon rubber cushions 216 and arepositioned to engage the wrap-around part of a vehicle bumper with theserubber cushions when the front wheels of the vehicle are lodged in therollers 35 and 37 of the Merrill aligner 33. When the front wheels ofthe vehicle have been so positioned, the braces 212 are moved inwardlyby the hydraulic cylinders 215 toward the vehicle on the track 214 untilthe rubber cushions 216 engage the wraparound part of the bumper of thevehicle and firmly hold the front of the vehicle in position. Becausethe carriages 217, on which the rubber cushions are mounted, have alimited horizontal movement with respect to the braces 212, the braces212 engaging the vehicle and holding the vehicle on the rollers 35 and37 will not interfere with the caster reading operation. The moveablecarriages permit the pivoting of the vehicle frame that occurs when thefront wheels are turned 7 /2 to the right and left during the casterreading procedure while still preventing the vehicle frame from movingsideways.

When the vehicle is driven off the rollers 35 and 37 after the alignmenthas been checked, the vehicle wheels exert force on the carriagesmounting the rollers 35 and 37 tending to move these carriages forward.This action automatically activates table locks which hold the carriagesin position and prevent them from being banged about as vehicle wheelspass over them. A switch is provided in the pendant 88 to release thetable locks.

FIG. 12 illustrates the system for testing the unbalance of a frontwheel of the vehicle. The system as shown in FIG. 12 makes use of avibration detector 218, which is attached to the suspension assembly ofthe front wheel being tested, and preferably on the lower control arm ofthis assembly. As shown in FIG. 12, the output signal of the vibrationdetector is fed through a low pass filter 220 and then to meter 222which indicates the amplitude of the filtered signal. When the wheel isrotated, the vibration detector 218 mounted on the wheel suspensionassembly will produce an output signal which varies in accordance withthe amount of wheel unbalance. This output signal will be at a frequencyequal to the revolutions per second that the wheel is rotated. The lowpass filter 220 filters out signals and noise in the output signal ofthe vibration detector above the frequency of the signal caused by thewheel unbalance and serves to eliminate these extraneous signals. Therewill be no substantial extraneous signals or noise in the output of thevibration detector 218 below the frequency of the signal caused by wheelunbalance. The measurement of the wheel unbalance of the front wheels ofthe vehicle is taken when the front wheels of the vehicle are positionedon the rollers 29 and 31 of the dynamometer and these rollers are usedto impart the rotation to the wheels required for the unbalancemeasurement. A separate system such as that shown in FIG. 12 isconnected to the suspension assembly of each front wheel in the testprocedure so that the unbalance of both front wheels can be measuredsimultaneously.

Two diagnosticians are employed at the diagnostic center to carry outthe tests and diagnoses on the automotive vehicles. The procedure oftesting and diagnosis on each vehicle is planned to take the leastpossible amount of time per vehicle being tested so as to make thecomplete testing and diagnosis of all manner of malfunctionings ofautomotive vehicles economically practical. To achieve this purpose theschedule of testing procedure eliminates lost or wasted time by thediagnosticians.

To facilitate the description of the procedure, the diagnosticians aredesignated A and B. While diagnostician B is busy with the precedingvehicle, diagnostician A drives the next vehicle up to the entrance 17.When the vehicle passes over the treadle 43, the entrance door raisesautomatically and diagnostician A drives the vehicle through theentrance 17 to the first testing station in which the vehicle is in theposition shown in FIG. 13. In proceeding to this testing station, thevehicle passes over the :treadle 44 and this action causes the entrancedoor to close again automatically. When the vehicle is positioned at thefirst testing station, the front wheels of the vehicle will bepositioned between the rollers of the dynamometer. At this time the liftfor the dynamometer will be in its raised position so the front wheelsof the vehicle will be resting on the dynamometer lift. Thediagnostician A then gets out of the vehicle and checks the tires of thevehicle and adjusts their pressure. At this time diagnostician A alsoattaches the vibration detectors of the wheel unbalanced detectionsystems illustrated in FIG. 12 to the front wheel suspension assemblies.Next the diagnostician A checks the transmission fluid level and obtainsa sample of the fluid for purposes of analysis. Diagnostician A thenchecks the radiator, the engine oil level, the fan belt, the hoses, theheat riser, the headlights and other lights on the vehicle, the parkbrake, the horn, the wipers, the turn signals, checks for audibleexhaust leakage, and measures the battery capacity. A Hoppy Lev-L-Litemanufactured by Hopkins Manufacturing Company of Emporia, Kansas, isused to check the alignment of the headlights. Meanwhile during thistime diagnostician B has driven the preceding car out of the diagnosticbay from exit 19 and discusses the diagnosis on the preceding vehiclewith the owner. After performing the checks described above,diagnostician A actuates the foot treadle 96. This action causes thedynamometer to lower its wheel left and the positioning unit to lowerthe pendant 84 to the extended position. Diagnostician A gets into thevehicle and sition.

13 then energizes the dynamometer motor so that the rollers 29 and 31drive the front wheels of the vehicle. Diagnostician A controls theoperation of the dynamometer when the vehicle is in the position shownin FIG. 13 by means of switches on the control pendant 84, which will bein its extended position and hang next to the drivers window when thevehicle is in this position. Thus the driver can control the operationof the dynamometer from the drivers seat, and valuable time is saved.While the rollers 29 and 31 are driving the front wheels, the horsepowerrequired to drive the front wheels is read by-the diagnostician A on thehorsepower meter 146 and recorded. This horsepower is referred to asparasitic horsepower. The diagnostician A also reads the balance meter,148 and records this reading. This reading provides the parasitichorsepower balance of the front wheels. Atthis time he also reads andrecords the amount of front wheel unbalance indicated by the meters 222in the wheel unbalance detection systems attached to the front wheelsuspension assemblies. Then while the dynamometer 27 is driving thefront wheels, the diagnostician A applies the brakes, and while thebrakes are applied he reads the horsepower meter 146. This gives a.reading of the efliciency of the front wheel brakes. While the brakesare applied the diagnostician A also reads the balance meter 148 andrecords this reading, which is an indication of the balance of the frontwheel brakes. While the parasitic horsepower and brake tests on thefront wheels are being carried out by diagnostician A, diagnostician Benters the diagnostic bay and performs an analysis on the transmissionfluid sample obtained from the vehicle by diagnostician A. This analysisof the transmission fluid determines the degree of oxidation of thetransmission fluid. If the oxidation of the transmission fluid is toohigh, then the fluid should be changed to avoid damaging the vehicletransmission. The tests for the oxidation of the fluid is fullydescribed in a copending application entitled Method for EstimatingQuickly the Neutralization Number for Automatic Transmission Fluid,Serial No. 241,168 invented by Charles Frederick Feasley and FernandoAlbert Pellicciotti and filed on the same day as the presentapplication. When diagnostician B has completed the analysis of thetransmission fluid and diagnostician A has completed the brake test onthe front wheels of the vehicle,

diagnostician B disconnects the vibration detectors from the front wheelsuspension assemblies. Diagnostician A then stops the dynamometer motorand actuates the wheel lift between the rollers 29 and 31 by means ofcontrol switches on the pendant 84. The switch that actuates the wheellift also actuates the positioning unit 90, which then retracts thependant 84 to its raised po- The wheel lift raises the front wheels outfrom between .the rollers 29 and 31 so that the vehicle can be drivenforward. Diagnostician A then drives the vehicle forward and runs overthe treadle 97, which action causes the dynamometer 27 to lower its liftand the positioning unit 92 to lower the pendant 86 to its extendedposition. Diagnostician A drives the vehicle for- Warduntil the rearwheels of the vehicle are on the rollers 29 and 31 of the dynamometer27. At this time the vehicle will be in the position shown in FIG. 14.Diagnostician B then walks to the front of the car and sets checks onthe front wheels to hold the vehicle rear wheels 7 will then beconnected between the fuel pump and the carburetor, and .the fuelpressure meter 190 will be connectedto measure the pressure in the fuelline between the fuel pump and the carburetor. While diagnostician B isconnecting up the fuel flow meter 184 and the fuel pressure meter 19!),diagnostician A gets out of the vehicle and inserts the combustionefliciency sample hose 156 in the tailpipe of the vehicle and thenconnects the engine scope to the high voltage output of the ignitioncoil and the ignition wire of the No. 1 cylinder, as described above.Also while the diagnostician B is connecting up the fuel flow meter 184and the fuel pressure meter 190, the diagnostician A connects the vacuumgauge 160 to the engine manifold. Diagnostician B then connects the voltamp tester 162 to the engine. Diagnostician B than connects the switchto the primary of the ignition coil and throws the switch to theposition in which it shorts out the primary. Meanwhile, diagnos tician Agets back into the drivers seat. Diagnostician A then engages the enginestarter, and diagnostician B reads and records the cranking voltagewhich will be indicated by the voltmeter of the volt amp tester. 'If thecranking voltage is not within specification limits, diagnostician Bthen reads and records the ampere draw, which will be indicated by theammeter of the volt amp tester when the primary of the inition coil isshorted out and the starter switch is engaged. Diagnostician B thenpositions the switch 110 to the position in which it connects the enginetachometer to the primary of the ignition coil. Diagnostician A thenstarts the vehicle engine an lets it idle. While the engine is idling,diagnostician A reads and records the engine r.p.m. shown on the enginetachometer 112, thus obtaining an indication of the engine idle speed.Also While the engine is idling, diagnostician A reads the-vacuum gaugeto obtain the manifold vacuum at idle. The reading of the exhaust gasanalyzer 158 is read and recordedwhile the engine is idling by thediagnostician A to provide a reading of the combustion efliciency atidle. Diagnostician B, while the engine is idling, reads and records thebasic timing indicated by the spark advance indicator 116. DiagnosticianA then increases the engine speed gradually to 1200 r.p.m. as indicatedby the engine tachometer 112. While the engine speed is being graduallyincreased in this manner, diagnostician B reads the regulator cutoutclosing voltage, which will be indicated by the voltmeter of thevolt-amp tester 162. Diagnostician A then holds the engine speed at 1200r.p.m. as indicated by the engine tachometer 112, and reads and recordsthe exhaust analyzer 158, which will indicate combustion efliciency at1200 r.p. m. Diagnostician B, while the engine is being held at 1200r.p.m., closes the switch 181 on the volt amp tester 162 and reads theregulated voltage output of the generator indicated on the volt amptester 162. Diagnostician B then opens the switch 181 and diagnosticianA opens the throttle rapidly and returns to 1200 r.p.m. and at the sametime reads and records the indication of the exhaust analyzer 158 toobtain the carburetor accelerating pump efficiency. Meanwhile thediagnostician B synchronizes the engine scope 100, if necessary, andmakes a preliminary reading of the waveforms on the engine scope.Diagnostician A then increases the engine speed to 2500 r.p.m. and holdsthe engine speed at this value as indicated by the engine tachometer112. While the engine speed is held at 2500 r.p.m. the combustionefiiciency is read and recorded from the exhaust gas analyzer 158.Diagnostician B, while the engine speed is being held at 2500 r.p.m.,reads and records the maximum spark advance indicated by the sparkadvance indicator 116. Diagnostician A then returns the engine speed toidle gradually, and while this gradual return to idle is being carriedout by diagnostician A, diagnostician B reads and records the regulatorcutout opening amperes indicated by the volt arnp tester 162.Diagnostician A then after the engine speed reaches idle reads andrecords the fuel pump pressure meter 190. Diagnostician A next startsthe strip chart recolder 114 by actuating a switch in the pendant 86,which will be in its extended position and hang next to the driverswindow when the vehicle is in the position shown in FIG. 14.Diagnostician A then accelerates the car through all gears 15 whilediagnostician B observes the waveforms on the engine scope 100. Thestrip chart recorder will shut itself off automatically after apredetermined time interval. The time interval will be long enough toexceed the duration of the acceleration of the vehicle through all ofits forward speeds so that the chart of the engine and wheel speedversus time covers the full cycle of acceleration. Diagnostician A thenadjusts the engine speed until the miles per hour meter 158 indicatesthat the vehicle is driving the dynamometer 27 at 50 mph. DiagnosticianA then observes the speedometer and records the difference between thespeed indicated by the speedometer and that indicated by the miles perhour meter 150, to obtain a calibration of the speedometer. Then whilethe engine is driving the dynamometer rollers at 50 mph. as indicated bythe miles per hour meter 150, the diagnostician A reads the fuel flowindicated by the flow meter 184. This indication of the fuel flow meter1-84 is then used to determine the miles per gallon obtained by thevehicle at 50 mph. Diagnostician A then opens the throttle of thevehicle to wide open. While the vehicle is accelerating diagnostician Areads the rate meter 151 to obtain an indication of the acceleration ofthe vehicle. Diagnostician A then returns the vehicle to 50 mph,energizes the dynamometer motor by means of a switch at pendant 86 andopens the throttle to wide open. While the throttle is at wide open,diagnostician A observes the maximum horsepower generated by the vehicleas indicated by the horsepower meter 146. Also while the throttle iswide open the diagnostician A reads and records the fuel pressureindicated by the fuel pressure meter 190. During this time diagnosticianB continues .to observe the waveforms on the engine scope. DiagnosticianA then closes the throttle and places the transmission of the vehicle inneutral. At this time diagnostician B records the conclusions reachedfrom observation of the waveforms depicted by the engine scope. Herecords the dwell and whether or not the firing voltage is satisfactoryand whether or not the condition of the points, ignition wires, thecoil, the condenser, and the distributor drive, lobes and bearings aresatisfactory. Diagnostician A then observes the parasitic horsepower forthe rear wheels indicated by the horsepower :meter 146 and observes theparasitic horsepower balance for the rear wheels indicated by thebalance meter 148. Next diagnostician A applies the brakes and observesthe reading of the horsepower meter 146 to deter-mine the efficiency ofthe rear brakes. While the brakes are applied, diagnostician A alsoobserves the reading of the balance meter 148 to determine the balanceof the rear brakes. While the car is being put through these paces, thediagnostician B disconnects all the equipment from the vehicle exceptthe fuel flow meter, fuel pressure meter, and the combustion efficiencyanalyzer. Diagnostician A .then turns off the dynamometer motor andstops the rear wheels with the vehicle brakes. Diagnostician A thenturns off the vehicle engine and records the pertinent data on the datasheet. While diagnostician A is performing these operations,diagnostician B disconnects the fuel flow meter 184 and the fuelpressure meter 190 from the fuel system and reconnects the original fuellines of the vehicle. Diagnostician A then again starts the engine anddiagnosticianv B observes the fuel system to see if there are any fuelleaks. Diagnostician B then installs the air cleaner and tears therecorded chart off from the strip chart recorder 114. Diagnostician Bthen gives this strip chart to diagnostician A and diagnostician Aattaches the strip chart to the data sheet. Diagnostician B then removesthe combustion efiiciency sample hose 156 of the exhaust gas analyzer158 from the exhaust pipe and then diagnostician A actuates thedynamometer lift by means of a control switch on the pendant 86 to raisethe rear wheels of the vehicle out from between the rollers 29 and 31.,The operation of this control switch 16 also actuates the positioningunit 94, which .then lowers the pendant 88 to its extend-ed position.Diagnostician A then drives the vehicle forward until the front wheelsare in the rollers 35 and 37 of the Merrill aligner 33, as shown in FIG.15. Diagnostician B then leaves the diagnostic bay to pick up the nextvehicle to be diagnosed. Diagnostician A then releases the table locksfor the Merrill aligner and actuates the horizontal stabilizer for theMerrill aligner by means of switches on the pendant 88. The hydraulicpistons of the horizontal stabilizer then drive the braces 212 inwardlyuntil the rubber cushions engage the wrap-around part of the bumper ofthe vehicle and hold the vehicle in place. Diagnostician A then checksthe wheel alignment on the Merrill aligner 33 by reading the amount oftoe, camber and caster. Diagnostician A operates the Merrill aligner bymeans of switches on the pendant 88 to take these readings entirelywhile sitting in the drivers seat of the vehicle. After these readingsare taken, diagnostician A actuates a switch on the pendant 88, whichswitch actuates the horizontal stabilizer to retract the braces 212 fromthe vehicle, actuates the positioning unit 94 to raise the pendant 88 toits retracted position, and actuates the positioning mechanism for theexit door to raise the exit door. Diagnostician A then drives thevehicle out of the diagnostic bay through the exit 19 and passes overthe treadle 46. In response to the vehicle passing over the treadle 46,the positioning mechanism for the exit door lowers the exit door to itsclosed position. Diagnostician A then enters the customer lounge todiscuss the results of the analysis with the customer. Whilediagnostician A is performing the wheel balance and wheel alignmentchecks and discussing the results of the analysis with the customer,diagnostician B has already started the test procedure on the nextvehicle. On the next vehicle, diagnostician B performs the duties thatwere performed by diagnostician A on the preceding vehicle, and viceversa.

Many modifications may be made to the above de scribed specificembodiment of the invention without departing from the spirit and scopeof the invention, which is defined in the appended claims.

What is claimed is:

1. In a system provided for rapid, eflicient, uniform diagnoses of aplurality of in line closely following, independently, intermittentlymoving automotive road vehicles to determine and identify deficientcharacteristics of each thereof by testing each said vehicle at each ofa plurality of stations as said vehicle is rolled in normal manner toand beyond each said station in proceeding to a point of exit, wherebyeach vehicle will be diagnosed to substantially the same and overallextent sufficient to provide a master record of its faults and therebypermit its repair and correction as desired subsequent to diagnosis,comprising a diagnostic passageway having an entrance and an exit,constructional means spacing said plurality of stations along saidpassageway thereby adapting same to receive said line of vehicles withone vehicle at at least each of a majority of said stations with workingspace between said respective vehicles, means determining the width ofsaid passageway at least sufficiently wide to permit lengthwise transitof said line of vehicles and sutficiently narrow to requiresubstantially lengthwise transit of each successive vehicle in said linethrough each successive station, diagnostic test equipment operative ateach said station adapted for a different diagnostic test sequentiallyon each respective vehicle in said line when said vehicles are rolledsuccessively to said station, dynamic vehicle testing means at at leastone of said stations in energy transmission engagement successively witha rotating wheel of each repective vehicle in said line when saidvehicles are rolled successively to said station, and diagnostic testequipment operative simultaneously from different stations adapted forinitiating a diagnostic test on at least one vehicle in said line priorto completion of a different diagnostic test on another vehicle in saidline, whereby a large number of vehicles may be diagnosed sequentiallyand substantially continuously for overall operation as aforesaidincluding simulated road operation, thereby to provide information ondeficient conditions and performance characteristics of each vehicle insaid line sufiicient to enable correction without actual road testing orfurther general diagnosis, the improvement which comprises diagnostictest equipment operative from at least one said station adapted toperform on each successive vehicle in said diagnostic rline sequentiallyat least one test which entails both control of said diagnosticequipment operative from said station and control of vehicle engineoperation which is normally accomplished from the vehicle drivers seatby means of the vehicle ignition switch and engine accelerator, controlmeans operative from said one station for controlling the diagnostictest equipment operative from said station, and means for supportingsaid control means adjacent the drivers seat window of each respectivevehicle in said line when said vehicle is rolled into test position asaforesaid at said one station, said support means comprising anchormeans in substantially fixed position longitudinally of said passageway,and means for attaching said control means to said anchor means for notmore than limited movement thereof relative to said anchor meanssutficient substantially only to enable placement of said control meansadjacent drivers seat windows of respective vehicles in said linepositioned successively at said one station, whereby both the diagnostictest equipment operation and the vehicle operation for each said test ofthe kind aforesaid on each vehicle in said line sequentially can becontrolled from the vehicle drivers seat when the drivers seat window isopen thereby to shorten further the diagnosis time for each vehicle andto make more rapid and efi'icient the sequential diagnosis of largenumber of vehicles.

2. The system of claim 1 in which the high capability of the system forlarge throughput of diagnosed vehicles per day is further enlarged by aplurality of instruments included in said diagnostic test equipmentoperative at each said station and adapted for a different diagnostictest sequentially on respective vehicles in said line when said vehiclesare rolled successively to each said station, and an instrument carriagesupporting a plurality of said instruments, a runway for said carriageextending substantially longitudinally of said diagnostic passageway,said runway and said carriage thereon being out of the way of the lineof vehicles traversing said passageway and of diagnostic tests on saidvehicles, to enable movement of said carriage along a substantialproportion of the length of said passageway to and between a pluralityof said diagnostic stations and adapted thereby for diagnostic use atdifferent stations, and restraining means for limiting the movement ofsaid instrument carriage transversely of said passageway, likewise outof the way of the line of vehicles traversing said passageway and ofdiagnostic tests on said vehicles, to limit transverse movement of saidcarriage substantially to movement thereof required for use of theinstruments supported thereon in diagnostic tests at said stations.

3. The diagnostic system of claim 1 in which at least one diagnostictest unit included in said diagnostic test equipment comprises saiddynamic vehicle testing means.

4. The automotive road vehicle diagnostic system of claim 3 in whichsaid dynamic vehicle testing means comprises a major diagnostic unitadapted for energy transfer engagement with a plurality of rotatingtires of each vehicle in said line successively to simulate road drivingand adapted to engage the front tires of each successive vehicle in saidline, control means operative for controlling said diagnostic unitduring each energy transfer engagement between said unit and front tiresof successive vehicles in said line, said major diagnostic unit alsobeing adapted at a time different than said engagement with the fronttires to engage the rear tires of successive vehicles in said line,separate control means operative for controlling said diagnostic unitduring each energy transfer engagement between said unit and rear tiresof successive vehicles in said line, means for supporting during saidengagement with front tires said first mentioned control means adjacentthe drivers seat window of each vehicle in said line when eachrespective vehicle is rolled into such engagement with its front tires,and means for supporting during said engagement with rear tires saidseparate control means likewise adjacent the drivers seat window of eachvehicle in said line when each respective vehicle is rolled into suchengagement with its rear tires, whereby all front and rear wheel testson said major diagnostic unit for each vehicle in said line successivelycan be conducted and controlled continuously from the drivers seatincluding positioning of each vehicle for said tests, and controllingboth the operation of the diagnostic unit and the operation of eachrespective vehicle during said tests.

5. The system of claim 4 in which the tests performed by said majordiagnostic unit includes wheel balance and includes rear wheel tests atdifferent engine driving loads and speeds, and which system alsocomprises another major diagnostic unit adapted for front vehicle wheelalignment, and separate control means for said wheel alignment unitlikewise positioned adjacent the drivers seat window of each vehicle insaid line when each respective vehicle is rolled into front wheelalignment engagement with said wheel alignment unit, whereby all theaforesaid tests, including positioning of each vehicle for said tests,controlling the operations of the respective diagnostic units, andcontrolling the operations of the respective vehicles during said testscan be accomplished from the drivers seats of the respective vehicles.

6. In a system provided for rapid, etficient, uniform diagnoses of aplurality of in line closely following, independently, intermittentlymoving automotive road vehicles to determine and identify deficientcharacteristics of each thereof by testing each said vehicle at each ofa plurality of stations as said vehicle is rolled in normal manner toand beyond each said station in proceeding to a point of exit, wherebyeach vehicle will be diagnosed to substantially the same and overallextent sufficient to provide a master record of its faults and therebypermit its repair and correction as desired subsequent to diagnosis,comprising a diagnostic passageway having an entrance and an exit,constructional means spacing said plurality of stations along saidpassageway thereby adapting same to receive said line of vehicles withone vehicle at at least each of a majority of said stations with workingspace between said respective vehicles, means determining the width ofsaid passageway at least sufficiently wide to permit lengthwise transitof said line of vehicles and suiticiently narrow to requiresubstantially lengthwise transit of each successive vehicle in said linethrough each successive station, diagnostic test equipment operative ateach said station adapted for a different diagnostic test sequentiallyon each respective Vehicle in said line when said vehicles are rolledsuccessively to each said station, dynamic vehicle testing means at atleast one of said stations in energy transmission engagementsuccessively with a rotating wheel of each respective vehicle in saidline when said vehicles are rolled successively to said station, anddiagnostic test equipment operative simultaneously from dilferentstations adapted for initiating a diagnostic test on at least onevehicle in said line prior to completion of a different diagnostic teston another vehicle in said line, whereby a large number of vehicles maybe diagnosed sequentially and substantially continuously for overalloperation as aforesaid including simulated road operation, thereby toprovide information on deficient conditions and performancecharacteristics of each vehicle in said line sutficient to enablecorrection without actual road testing or further general diagnosis, theimprovement which comprises a plurality of instruments included in saiddiagnostic test equipment opera tive at each said station and adaptedfor a different diagnostic test sequentially on respective vehicles insaid line when said vehicles are rolled successively to each saidstation, an instrument carriage supporting a plurality of saidinstruments, a runway for said carriage extending substantiallylongitudinally of said diagnostic passageway, said runway and saidcarriage thereon being out of the way of the line of vehicles traversingsaid passageway and of diagnostic tests on said vehicles, to enablemovement of said carriage along a substantial proportion of the lengthof said passageway to and between a plurality of said diagnosticstations, and restraining means for limiting the movement of saidinstrument carriage transversely of said passageway, likewise out of theway of the line of vehicles traversing said passageway and of diagnostictests on said vehicles, to limit transverse movement of said carriagesubstantially to movement thereof required for use of the instrumentssupported thereon in diagnostic tests at said stations, thereby to speedup the diagnosis of large numbers of vehicles moving sequentially insaid line and to facilitate the use of said instruments for tests on aplurality of vehicles and on vehicles of different sizes andconstruction features.

7. The system of claim 6 in which the said instruments supported by andmovable with said instrument carriage include a measuring instrumentadapted for connection to the power plant of each vehicle in said linesuccessively and operable to measure performance characteristics there-References Cited by the Examiner UNITED STATES PATENTS 850,439 4/ 1907Morgan 2l222 2,002,777 5/1935 Johnson 200.8 2,049,025 7/ 1936 Rosebrook20O.8 2,130,900 9/ 1938 Presbrey 73--1 17 2,702,432 2/1955 Martin 73-117XR 3,020,753 2/1962 Maxwell 73-117 OTHER REFERENCES Article: ShopPlanning and Layout. -vol. 79, page 47, August 1960, TLl M88.

Bockemuehl: R. R. Instrumentation for Low-Temperature AutomotiveTesting. In ISA Journal, April 1957, p. 123.

In Motor Age,

RICHARD C. QUEISSER, Primary Examiner.

DAVID SCHONBERG, Examiner.

1. IN A SYSTEM PROVIDED FOR RAPID, EFFICIENT, UNIFORM DIAGNOSES OF A PLURALITY OF IN LINE CLOSELY FOLLOWING, INDEPENDENTLY, INTERMITTENTLY MOVING AUTOMOTIVE ROAD VEHICLES TO DETERMINE AND IDENTIFY DEFICIENT CHARACTERISTICS OF EACH THEREOF BY TESTING EACH SAID VEHICLE AT EACH OF A PLURALITY OF STATIONS AS SAID VEHICLE IS ROLLED IN NORMAL MANNER TO AND BEYOND EACH SAID STATION IN PROCEEDING TO A POINT OF EXIT, WHEREBY EACH VEHICLE WILL BED IAGNOSED TO SUBSTANTIALLY THE SAME AND OVERALL EXTENT SUFFICIENT TO PROVIDE A MASTER RECORD OF ITS FAULTS AND THEREBY PERMIT ITS REPAIR AND CORRECTION AS DESIRED SUBSEQUENT TO DIAGNOSIS, COMPRISING A DIAGNOSTIC PASSAGEWAY HAVING AN ENTRANCE AND AN EXIT, CONSTRUCTIONAL MEANS SPACING SAID PLURALITY OF STATIONS ALONG SAID PASSAGEWAY THEREBY ADAPTING SAME TO RECEIVE SAID LINE OF VEHICLES WITH ONE VEHICLE AT AT LEAST EACH OF A MAJORITY OF SAID STATIONS WITH WORKING SPACE BETWEEN SAID RESPECTIVE VEHICLES, MEANS DETERMINING THE WIDTH OF SAID PASSAGEWAY AT LEAST SUFFICIENTLY WIDE TO PERMIT LENGTHWISE TRANSIT OF SAID LINE OF VEHICLES AND SUFFICIENTLY NARROW TO REQUIRE SUBSTANTIALLY LENGTHWISE TRANSIT OF EACH SUCCESSIVE VEHICLE IN SAID LINE THROUGH EACH SUCCESSIVE STATION, DIAGNOSTIC TEST EQUIPMENT OPERATIVE AT EACH SAID STATION ADAPTED FOR A DIFFERENT DIAGNOSTIC TEST SEQUENTIALLY ON EACH RESPECTIVE VEHICLE IN SAID LINE WHEN SAID VEHICLE TESTING MEANS SUCCESSIVELY TO SAID STATION, DYNAMIC VEHICLE TESTING MEANS AT AT LEAST ONE OF SAID STATIONS IN ENERGY TRANSMISSION ENGAGEMENT SUCCESSIVELY WITH A ROTATING WHEEL OF EACH RESPECTIVE VEHICLE IN SAID LINE WHEN SAID VEHICLES ARE ROLLED SUCCESSIVELY TO SAID STATION, AND DIAGNOSTIC TEST EQUIPMENT OPERATIVE SIMULTANEOUSLY FROM DIFFERENT STATIONS ADAPTED FOR INITIATING A DIAGNOSTIC TEST ON AT LEAST ONE VEHICLE IN SAID LINE PRIOR TO COMPLETION OF A DIFFERENT DIAGNOSTIC TEST ON ANOTHER VEHICLE IN SAID LINE, WHEREBY A LARGE NUMBER OF VEHICLES MAY BE DIAGNOSED SEQUENTIALLY AND SUBSTANTIALLY CONTINUOUSLY FOR OVERALL OPERATION AS AFORESAID INCLUDING SIMULATED ROAD OPERATION, THEREBY TO PROVIDE INFORMATION ON DEFICIENT CONDITIONS AND PERFORMANCE CHARACTERISTICS OF EACH VEHICLE IN SAID LINE SUFFICIENT TO ENABLE CORRECTION WITHOUT ACTUAL ROAD TESTING OR FURTHER GENERAL DIAGNOSIS, THE IMPROVEMENT WHICH COMPRISES DIAGNOSTIC TEST EQUIPMENT OPERATIVE FROM AT LEAST ONE SAID STATION ADAPTED TO PERFORM ON EACH SUCCESSIVE VEHICLE IN SAID DIAGNOSTIC LINE SEQUENTIALLY AT LEAST ONE TEST WHICH ENTAILS BOTH CONTROL OF SAID DIAGNOSTIC EQUIPMENT OPERATIVE FROM SAID STATION AND CONTROL OF VEHICLE ENGINE OPERATION WHICH IS NORMALLY ACCOMPLISHED FROM THE VEHICLE DRIVER''S SEAT BY MEANS OF THE VEHICLE IGNITION SWITCH AND ENGINE ACCELERATOR, CONTROL MEANS OPERATIVE FROM SAID ONE STATION FOR CONTROLLING THE DIAGNOSTIC TEST EQUIPMENT OPERATIVE FROM SAID STATION, AND MEANS FOR SUPPORTING SAID CONTROL MEANS ADJACENT THE DRIVER''S SEAT WINDOW OF EACH RESPECTIVE VEHICLE IN SAID LINE WHEN SAID VEHICLE IS ROLLED INTO TEST POSITION AS AFORESAID AT SAID ONE STATION, SAID SUPPORT MEANS COMPRISING ANCHOR MEANS IN SUBSTANTIALLY FIXED POSITION LONGITUDINALY OF SAID PASSAGEWAY, AND MEANS FOR ATTACHING SAID CONTROL MEANS TO SAID ANCHOR MEANS FOR NOT MORE THAN LIMITIED MOVEMENT THEREOF RELATIVE TO SAID ANCHOR MEANS SUFFICIENT SUBSTANTIALLY ONLY TO ENABLE PLACEMENT OF SAID CONTROL MEANS ADJACENT DRIVER''S SEAT WINDOWS OF RESPECTIVE VEHICLES IN SAID LINE POSITIONED SUCCESSIVELY AT SAID ONE STATION, WHEREBY BOTH THE DIAGNOSTIC TEST EQUIPMENT OPERATION AND THE VEHICLE OPERATION FOR EACH SAID TEST OF THE KIND AFORE SAID ON EACH VEHICLE IN SAID LINE SEQUENTIALLY CAN BE CONTROLLED FROM THE VEHICLE DRIVER''S SEAT WHEN THE DRIVER''S SEAT WINDOW IS OPEN THEREBY TO SHORTEN FURTHER THE DIAGNOSIS TIME FOR EACH VEHICLE AND TO MAKE MORE RAPID AND EFFICIENT THE SEQUENTIAL DIAGNOSIS OF LARGE NUMBER OF VEHICLES. 